Pro12: Ulster v Scarlets (Sun)

Pro12: Ulster v Scarlets
Venue: Kingspan Stadium, Belfast Date: Sunday, 21 February Kick-off: 14:30 GMT
Coverage: Live on BBC Two Northern Ireland, S4C, BBC iPlayer and online; live score updates online plus highlights on Scrum V, BBC Two Wales from 18:20 GMT on Sunday and later on demand and online

Fly-half Paddy Jackson will lead Ulster for the first time in Sunday's crucial Pro12 match against the Scarlets.

The 24-year-old has been disappointed at not being involved in Ireland's Six Nations campaign, but his availability is a boost to table-toppers Ulster.

Welsh squad player Aled Davies starts at scrum-half for the Scarlets after being released by Warren Gatland and he partners Aled Thomas at halfback.

Thomas replaces injured Steve Shingler as two of the Pro12's top four meet.

Fourth-placed Scarlets, just a point behind leaders Ulster, drop Rhodri Williams to the bench to accommodate uncapped Welshman Davies.

Ulster pair Ruan Pienaar and Ian Humphreys, who had to go through 'return to play' protocols following concussion, are on the replacements' bench.

Rob Herring has a slight hamstring injury so John Andrew will make his first senior start at hooker

Rory Best, Jared Payne and Andrew Trimble are not available to Ulster as they are on international duty..

Ulster go into the 15th round of league action top of the table while Scarlets lie fourth, but only a point separates the two sides, who both won last week.

Pro12 form guide
Ulster (1st ): 12 Feb: Ulster 13-10 Glasgow; 5 Feb: Ulster 17-15 Dragons; 30 Jan:Treviso 13-32 Ulster 2 Jan: Ulster 7-9 Munster
Scarlets (4th): 12 Feb: Scarlets 22-21 Edinburgh; 30 Jan: Connacht 30-17 Scarlets;10 Jan: Scarlets 21-19 Connacht; 1 Jan: Cardiff Blues 29-27 Scarlets

Scarlets beat Edinburgh 22-21 and Ulster triumphed 13-10 over Glasgow last Friday.

The west Wales region have not won away in the Pro12 since beating Trevisoin December, 2015.

Meanwhile Ulster have secured centre Stuart Olding until the end of the 2018-19 season and prop Rhodri Jones is to depart Scarlets for Ospreys at the end of the current campaign.

Ulster: S Olding, C Gilroy, D Cave, L Marshall, J Stockdale, P Jackson (capt), P Marshall; A Warwick, J Andrew, R Lutton, A O'Connor, F van der Merwe, R Diack, C Henry, R Wilson.

Replacements: J Murphy, K McCall, B Ross, P Browne, C Ross, R Pienaar, I Humphreys, S Arnold.

Scarlets: M Collins, G Owen, R King, H Parkes (capt), DTH van der Merwe, A Thomas, A Davies, P John, K Myhill, P Edwards, G Earle, D Bulbring, A Shingler, W Boyde, M Allen.

Replacements: R Elias, D Evans, R Jones, M Paulino, R Pitman, R Williams, D Jones, S Evans.

Referee: Ian Davies (WRU)

Assistant referees: Nigel Correll, John Carvill (IRFU)

Citing commissioner: Eddie Walsh (IRFU)

TMO: Alan Rogan (IRFU)